U21a Temporary Sign – Temporary Narrowing (Right Lane, 3 to 2), 80x120 cm, Class II

U21a Temporary Sign – Temporary Narrowing (Right Lane, 3 to 2), 80x120 cm, Class II

The version for roads with three lanes each way: the right lane closes and traffic continues on the other two. It measures 80x120 cm and has class II prismatic sheeting, suited to major roads with fast traffic.

Why class II

On national roads and lit streets, permanent signing is often class II, and SR 1848-2 requires temporary signs on the same section to have at least the same class. Class II (RA2) prismatic sheeting returns three to four times more light than class I and has a guaranteed 10-year service life, so the sign can be used on one site after another.

Where it goes, under SR 1848-1:2024

It shows drivers, before the work zone, which lane closes and where traffic continues. The content of the sign is chosen to match the road layout; this version shows 3 lanes becoming 2, with the right lane closed. SR 1848-1:2024 sets no specific distance for this sign: it is installed under the technical regulations in force for signing roadworks, following the signing layout of the works. Like any sign, it normally goes on the right-hand side of the direction of travel, so that it can be seen from at least 50 m in built-up areas and at least 100 m outside them (SR 1848-2).

What the roadworks rules require (Order 1112/411/2000)

The sign belongs to the advance signing, which is installed first, ahead of the work zone in the direction of travel, with at least 50 cm of clear space outside the carriageway. The rules require signs to be stood on the ground first, to check that they are clearly visible, and only then fixed to a support; no more than two signs go on the same support or side by side, and on one-way roads or bends they can be repeated on the left side or above the road.

On public roads, works are signed under the methodological rules approved by Order MI/MT no. 1112/411/2000. The road closure or traffic restriction is approved by the road authority, with the traffic police's agreement, on the basis of a signing layout endorsed as final, a copy of which the contractor keeps at the work site. The contractor installs, completes and maintains the signing for the whole job, removes it at the end and restores the original signing; accidents caused by incomplete or missing temporary signing are entirely the contractor's responsibility.

At night, if the existing signing on the road is retroreflective, the temporary signing must be retroreflective too and can be supplemented with flashing or sequential (“cascade”) amber lamps; on main and connecting streets in towns, retroreflective temporary signs are supplemented with flashing amber lamps.

Technical data

• 80x120 cm yellow panel with 3 lanes becoming 2, with the right lane closed;
• 1 mm galvanised steel sheet, with rounded corners and pressed edges, no sharp edges;
• electrostatically painted;
• class II (RA2) prismatic retroreflective sheeting, with a guaranteed 10-year service life;
• fixings included: 2 clamps for Ø48 mm posts and 4 bolts with nuts;
• compliant with SR EN 12899-1:2007, SR 1848-1:2024, SR 1848-2:2011 and SR 1848-3:2011.

Mounting and size

Fixings for the post are included: 2 clamps for Ø48 mm posts and 4 bolts with nuts; clamps for Ø60 mm posts are available on request. The bottom edge of the sign goes 1.50–2.50 m above the road or kerb, and the edge nearest the road 0.50–2.0 m from the road platform.

The 80x120 cm size is the one SR 1848-2 sets for national roads; motorways call for 120x180 cm, and other roads and streets for 65x85 cm. The class I sheeting version, 65x85 cm, is the U21a.